Manufacture of viscose silk



Get. 23, 12s..

EMILE BRONNERT, OF MULHOUSE, FRANCE. I

MANUFACTURE or VISCOSE, SILK.

No Drawing.

To all whom it may concern:

Be it known that I, EMILE BRoNNnn'r, a citizen of the Republic of France, residing in Mulhouse, Alsace Lorraine, France, have invented certain new and useful Improvements in the Manufacture of Viscose Silk, for which I filed applications in Germany Apr. 6, 1918; in 'Austria July 26, 1918; and in Hungary Sept. 30, 1918, and of which the following is a specification.

This invention relates to the manufacture of viscose silk and has for its object to produce much finer threads of. viscose silk than has heretofore been possible.

The conditions which must be realized for the effective spinning or manufacture of artificial silk according to the drawing method vary with the different processes employed, and in each particular case, can only be determined after a number of tedious trials .and long considerations.

In the case of nitro-cellulose silk, very fine threads have been produced by drawing out the jets of collodion in substances (e. 5;. oil of turpentine) which were known to absorb ether-alcohol but in which nevertheless, an equilibrium takes place so that sufficient solvent is leftin the thread to render it still soft and capable of being further drawn out. I

This manner of treatment, however, cannot 'be successfully employedin connection with processes using aqueous cellulose solutions.

In the case of cuprammonium or so-called cop er silk, the thread produced with an em or soda lye treatment is immediately coagulated too much to permit its being further drawn out, and if weaker. chemicals, such'as salts and the like he used the thread is deficient in the cohesion requisite for drawing so that a very fine thread cannot be produced by merely drawing out or stretchin%a thick thread.

omplicated apparatus would be needed to enable the desired degree of fineness of thread to be obtained by means of drawing,

for example the thread would have to be treated with great care in an almost frictionless coherent column of liquid maintained at atmospheric pressure.

In the case of viscose silk very fine threads of say two deniers have not heretofore been produced successfully on a commercial scale. Even with the usual'apertures of 0.10

mm. and with a thread drawing or winding Application filed July 8, 1920. Serial No. 394,840.

ofi speedof metres per minute it has not heretofore been possible to produce, threads under 5 to 6 deniers and of course still less with larger apertures. I

It is therefore all the more suprising'that in accordance with the present invention with a greater speed of drawing or winding off, We can draw very fine threads from the ordinary apertures of 0.10 mm. provided that on the one hand provision is made, as

for instance by means of so called Titer pumps, to maintain a certain, always uniform and accurately adjusted feed of viscose, that is to say, feedingthe viscose in uniform and exactly measured quantities to the apertures, and provided further that there are employed setting baths to render the jet of viscose entering the bath capable of being still drawn out to threads of say 2 deniers. Suitable baths for this purpose are for example acid sulphate solutions at an ordinary temperature, containing bisulphates of sodium in diluted sulphuric acid of about 20 er cent.-

do not wish to be restricted to the use of bisulphate of sodium only, but can also advantageously use a. mixture of the easily soluble sul hates of the f alkalies or earthmetals. lloreover bisulphate or bisulphite combinations may be used. Y

The degree of acidity can be easily adapted to the degree of maturity of the viscose. With viscose ripened for about90 hours at 18 C. the bath mentioned gives excellent direct results at an ordinary temperature. Any setting that may still be necessary may be effected by means of the same baths, but

heated for instance to 45 C. y 1

The subsequent treatment is the same as tlizlzzt usually employed'for ordinary viscose s1 It'has also been found that temperatures of the coagulating bath up to 45 C. are suitable and that with an increased temperature a greater lustre of the resultant product is obtained than with lower temperature.

In the foregoing process which I have termed the fine spinning process I am enabled to produce viscose silk threads of 6 to 2 deniers downwards, without narrowing the spinning openings.

What I claim is:-

1. The process of making artificial silk threads of a fineness from .6 to 2 deniers downwards, which comprises passing viscose through the usual apertures of 0.10 mm.

diameter into an acid coagulating solution which permits of the threads formed being drawn to a predetermined fineness, said solution consisting of an alkali earth or metal sulphate or bisulphate having sufficient sulphuric acid to constitute a 20% sulphuric acid solution.

2. The process according to claim 1 characterized in that the coagulated thread is subjected to a drawing-0d speed of 4:5 or more meters per minute.

3. The process according to claim 1 characterized in that when a high lustre thread is desired the viscose is'coagulated in a solution at a temperature of 40-50 C. 11

In witness whereof, I have hereunto signed my name in the presence of two subscribing witnesses.

' EMILE BRONNERT.

Witnesses V HENRY BRONNERT, RALPH BnoNNnnr. 

